Alexander Sepity d3e020a1e7 System sets and run criteria v2 (#1675) ... I'm opening this prematurely; consider this an RFC that predates RFCs and therefore not super-RFC-like. This PR does two "big" things: decouple run criteria from system sets, reimagine system sets as weapons of mass system description. ### What it lets us do: * Reuse run criteria within a stage. * Pipe output of one run criteria as input to another. * Assign labels, dependencies, run criteria, and ambiguity sets to many systems at the same time. ### Things already done: * Decoupled run criteria from system sets. * Mass system description superpowers to `SystemSet`. * Implemented `RunCriteriaDescriptor`. * Removed `VirtualSystemSet`. * Centralized all run criteria of `SystemStage`. * Extended system descriptors with per-system run criteria. * `.before()` and `.after()` for run criteria. * Explicit order between state driver and related run criteria. Fixes #1672. * Opt-in run criteria deduplication; default behavior is to panic. * Labels (not exposed) for state run criteria; state run criteria are deduplicated. ### API issues that need discussion: * [`FixedTimestep::step(1.0).label("my label")`](eaccf857cd/crates/bevy_ecs/src/schedule/run_criteria.rs (L120-L122)) and [`FixedTimestep::step(1.0).with_label("my label")`](eaccf857cd/crates/bevy_core/src/time/fixed_timestep.rs (L86-L89)) are both valid but do very different things. --- I will try to maintain this post up-to-date as things change. Do check the diffs in "edited" thingy from time to time. Co-authored-by: Carter Anderson <mcanders1@gmail.com>		2021-03-24 20:11:55 +00:00
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alien_cake_addict.rs	System sets and run criteria v2 (#1675)	2021-03-24 20:11:55 +00:00
breakout.rs	Make Commands and World apis consistent (#1703)	2021-03-23 00:23:40 +00:00